ByPass Large 1 inch or Standard 3/4 inch - How to Tell the Difference
By Pass Valve Large Version 7214383, WS15X10026 and High Flow 1" Valve Body
VS
Smaller Standard ( 3/4" ) valve body and By Pass Valve 7278434, WS15X10053
The By Pass used on the "standard" ( sometimes called 3/4" )
= BY PASS PN 7278434,
Looks similar to the "High Flow" ( sometimes called 1" )
= BY PASS PN 7214383
But are not interchangeable ( offset over 1/2" different ).

Note there are Two Size Valves.
Large ( on bottom ) is wider at valve connection than the Standard ( on top ).
The adapter outlets are closer on the Large, than on the Standard ( as shown ).

Also, newest version of the smaller by pass ( 7278434 ) have "handles" instead of "push plunger" ends.

And they are called 3/4" and 1",
but BOTH have 1" piping connections on the REAR.
So, the fact that you have 1" piping / fittings,
has NOTHING to do with whether your valve is the "Standard 3/4" or the "Large 1" Valve Size:
Additional SIZE determination,
REFERENCE the following:
3/4" Standard, ( 5 screws hold Valve Cover to Valve Body ).

Or
1" Large. ( 8 screws hold Valve Cover to Valve Body ).

And they use different size Seal Kits and Rotor Discs ( and Valve Body, Valve Cover, By Pass, etc ).
Standard 3/4" Rotor Disc is about 3 3/8" in diameter,

OR
Large 1" Rotor Disc is about 4 3/8" in diameter,

The Standard Version Seal Kit ( 7129716, WS35X10005 ) we sell is commonly used and smaller in size than the 1" ( Large ) valve version, so please check before ordering.
And the LARGER SIZE:
The Larger 1" Version Seal Kit ( 7185487, WS35X10020 ) is a full 1" larger, so please check if you are not sure before ordering.
For Model Number Reference, as to whether yours is 3/4" or 1" Valve design, see the Service Manual Listings on our website,
SEARS - Kenmore
or
GE Smartwater
or
Whirlpool
Also you should take a look at this animation from the Morton softener site - the link is below.
Their softener is another variant of the Ecowater/NorthStar/Sear/GE Smartwater type system.
The animations are almost identical to the animations on the Kenmore site, except the Morton animation also
shows the flow paths, dis-assembly and reassembly of the complete valve body, including all the o-rings.
It also shows the complete float assembly - Kenmore site doesn't show either of these assemblies last time I checked.
After the link is pulled up you have the option to run program - I had to click the button twice
- may just be my browser but I figured I'd mention it.
Morton System Saver Water Softener Animation; (Click Link Below)
https://www.mortonwatersofteners.com/interactive-animation/index.html
VS
Smaller Standard ( 3/4" ) valve body and By Pass Valve 7278434, WS15X10053
The By Pass used on the "standard" ( sometimes called 3/4" )
= BY PASS PN 7278434,
Looks similar to the "High Flow" ( sometimes called 1" )
= BY PASS PN 7214383
But are not interchangeable ( offset over 1/2" different ).
Note there are Two Size Valves.
Large ( on bottom ) is wider at valve connection than the Standard ( on top ).
The adapter outlets are closer on the Large, than on the Standard ( as shown ).
Also, newest version of the smaller by pass ( 7278434 ) have "handles" instead of "push plunger" ends.
And they are called 3/4" and 1",
but BOTH have 1" piping connections on the REAR.
So, the fact that you have 1" piping / fittings,
has NOTHING to do with whether your valve is the "Standard 3/4" or the "Large 1" Valve Size:
Additional SIZE determination,
REFERENCE the following:
3/4" Standard, ( 5 screws hold Valve Cover to Valve Body ).

Or
1" Large. ( 8 screws hold Valve Cover to Valve Body ).

And they use different size Seal Kits and Rotor Discs ( and Valve Body, Valve Cover, By Pass, etc ).
Standard 3/4" Rotor Disc is about 3 3/8" in diameter,
OR
Large 1" Rotor Disc is about 4 3/8" in diameter,
The Standard Version Seal Kit ( 7129716, WS35X10005 ) we sell is commonly used and smaller in size than the 1" ( Large ) valve version, so please check before ordering.
And the LARGER SIZE:
The Larger 1" Version Seal Kit ( 7185487, WS35X10020 ) is a full 1" larger, so please check if you are not sure before ordering.
For Model Number Reference, as to whether yours is 3/4" or 1" Valve design, see the Service Manual Listings on our website,
SEARS - Kenmore
or
GE Smartwater
or
Whirlpool
Also you should take a look at this animation from the Morton softener site - the link is below.
Their softener is another variant of the Ecowater/NorthStar/Sear/GE Smartwater type system.
The animations are almost identical to the animations on the Kenmore site, except the Morton animation also
shows the flow paths, dis-assembly and reassembly of the complete valve body, including all the o-rings.
It also shows the complete float assembly - Kenmore site doesn't show either of these assemblies last time I checked.
After the link is pulled up you have the option to run program - I had to click the button twice
- may just be my browser but I figured I'd mention it.
Morton System Saver Water Softener Animation; (Click Link Below)
https://www.mortonwatersofteners.com/interactive-animation/index.html